Prior art is known to include procedures and devices for machining objects using laser radiation that, for example, are used for shaping the cornea of the eye to correct poor vision. The required energy is brought into the tissue through pulsed laser radiation that is guided by scanning the sector of the lens from which tissue is to be removed.
More recent developments in connection with such ophthalmological surgical procedures for improving poor vision are using ultra-short pulse lasers to impart the energy and are known as fs-LASIK. The state of technology is described in R. Kurtz et al. “Femtosecond Laser Corneal Refractive Surgery”, Proc. SPIE 3591, 209 (1999).
Here the laser radiation is focused on a focal point of a magnitude of just a few micrometers in the cornea. At the focal point a plasma is generated, which quickly vaporizes immediately adjacent tissue, causing a separation of the tissue at this location.
This interaction between the laser radiation and the tissue is called photo-disruption. Since the photo-disruption is limited to a microscopically small area, it is possible to create precise surgical cuts within the eye to achieve a locally restricted separation of the corneal tissue. Targeted rows of such separation zones allow macroscopic cuts and a predetermined partial corneal volume can be isolated. The removal of this partial volume achieves a desired change in the refraction of the cornea and thus a correction of the poor vision. In the following, the method based upon photo-disruption is referred to as fs-LASIK.
The procedure is designed so that prior to the fs-LASIK procedure, an observation device, for example a microscope, is used to inspect the object of the procedure and to determine the parameters of the treatment, such as the intensity of the laser radiation, pulse sequences, length and location of the cuts, etc. Following this, the procedure is carried out using the laser scan device.
Usually, the results of the procedure are evaluated again with the help of the observation device. Following this, post-surgical steps are carried out, such as the removal of the excised volume and the wound care.